| IPP-10 and cycloxaprid were developed by East China University of Science and Technology as novel kind of neonicotinoid insecticides, which have high insecticidal activities, low toxicity and broad spetrum. The primary screening test proved that IPP-10 and cycloxaprid had good activities against sucking insects. Recently, significant increases in resistance were observed in a range of species after frequent field applications of neonicotinoid insecticides. Therefore, to investigate the insecticidal spetrum, mode of action and sublethal effect of IPP-10 and cycloxaprid will promote the research and agricultural application of them.Studies were carried out to investigate the toxicity of cycloxaprid against whitefly, grape leafhopper, cotton aphid and Aorea scutellaris by primary screening test, and the field efficacy experiments were also carried out. Besides, the contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles of IPP-10 and cycloxaprid were also studied, and the feeding behavior of aphids on IPP-10 and cycloxaprid treated wheat at a sublethal dose were also observed by electrical penetration graph technology. Results are as follows:(1) The primary screening tests demonstrated that cycloxaprid had good toxicity against whiteflies, grape leafhopper nymphs, cotton aphid and Aorea scutellaris with the LC50 values of 5.4 mg/L,2.2 mg/L,0.66 mg/L and 1.9 mg/L respectively. Meanwhile, the field efficacy experiments showed that cycloxaprid was very effective and had higher control efficacy against whiteflies than imidacloprid; cycloxaprid and imidacloprid were also effective against grape leafhopperrs. Although the control efficacy of cycloxaprid against cotton aphid in Shihezi district was low, cycloxaprid was very effective against cotton aphid in Linyi district.(2) IPP-10 and cycloxaprid had good contact and root-systemic activity. Moreover, IPP-10 had some degree basipetal translocation in wheat vascular bundles. The LC50 value of IPP-10 against Rhopalosiphum padi after foliar application and root treatment were 2.45 and 2.4 mg/L respectively, and IPP-10 can move to some degree from leaf to stem in the vascular bundles of wheat plant. The LC50 values of cycloxaprid against Sitobion avenae after foliar application and root treatment were 1.98 and 1.1 mg/L respectively, but IPP-10 can hardly move from leaf to stem.(3) The probing and feeding behaviour of aphids were significantly inhibited by sublethal dose of IPP-10 and cycloxaprid. R. padi treated with a sublethal dose of IPP-10 revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. Further analysis indicated that the numbers of E1, E2 and G bout of the sublethal dose of IPP-10 treated aphids were not significantly different from those of the blank aphids. However, the frequency of xylem ingesting waveform and phloem ingesting waveform (7.03±0.49 Hz and 1.96±0.071 Hz) produced by aphids on wheat treated with IPP-10 were significantly lower than that of blank aphids. So aphids treated with sublethal dose of IPP-10 had significantly reduced feeding, mass and fecundity, reaching reproductive maturity more slowly than those blank aphids. Sitobion avenae treated with a sublethal dose of cycloxaprid revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time of none probing (103.04±10.87min) and phloem salivation (50.80±7.26 min) were significantly prolonged. Besides, the numbers of E1 bout (3.40±0.34 times) of the sublethal dose of cycloxaprid treated aphids was significantly more than other treatments. Moreover, the frequency of xylem ingesting waveform (5.00±0.047 Hz) produced by aphids treated with cycloxaprid were significantly lower than that of blank aphids but higher than that of aphids treated with imdacloprid. While, the frequency of Phloem ingesting waveform produced by aphids treated with cycloxaprid was significantly lower than that of aphids treated with imdacloprid and distilled water. The results indicated that cycloxaprid and imidacloprid were also reduced the feeding of aphids in xylem and phloem, but cycloxaprid has higher inhibition on phloem ingestion than imidacloprid. But, cycloxaprid was lower than imidacloprid in inhibition of xylem ingestion.
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